A potentially hazardous condition which occasionally arises in the operation of escalators is a tendency of the rider's wearing apparel to rub against the stationary stainless steel vertical skirt member which laterally encloses the moving escalator. This friction between the moving article of clothing and the stationary skirt member causes certain materials to heat sufficiently that they soften and tend to adhere to the cast aluminum or cast iron step plate. Such adherence then tends to pull such article underneath the comb plate as the step plate disappears thereunder at the exit level of the escalator. Articles which are particularly vulnerable to this tendency include tennis shoes, over-shoes, clothing of a small child sitting on the escalator or long gowns. A very high proportion of the accidents which occur on a properly maintained escalator involve an article that is either wedged between the skirt and the step plate or between the step plate and the comb plate.
A prior art attempt to alleviate this condition has been made on escalator step plates manufactured by the Hitachi Company of Japan. As is conventional, such step plates have a series of closely spaced parallel grooves extending longitudinally along their upper surface, which grooves intermesh with the downwardly projecting fingers of the comb plate to aid in preventing articles from wedging in under the comb plate or floor plate. In the Hitachi step plate, the extreme lateral edges of each step plate have a raised shoulder which rises perpendicularly from the upper surface of the step plate. This configuration, which is formed integrally with the step plate, has not been entirely successful in avoiding the above-described problems. For example, it will not always guide an article away from the gap between the step plate and the skirt member; being formed integrally with the cast aluminum or cast iron step plate, it is subject to adherence by a soft semi-melted plastic article; it does not lend itself to permitting reduction in the width of the above described gap; it provides no solution for the numerous escalators which are already installed and operating.
Accordingly, it is the primary object of the present invention to provide an improved means for avoiding or reducing the potentially hazardous conditions described above.